Field
The present invention relates to a fuel cell.
Related Art
A fuel cell stack which is constituted by stacking a plurality of unit cells has current collectors for collecting electric power generated at each unit cell and supplying the collected power to outside. Since conductivity and corrosion resistance are required for the current collector, JP2009-187729A proposes a current collector having a layered structure comprised of a metal plate of good conductivity and a metal plate of good corrosion resistance.
In JP2009-187729A, the entire surface of the two kinds of stacked metal plates is covered with a layer made of conductive resin (hereinafter, referred to as a “joining layer”), and thereby the two kinds of metal plates are joined. Thus, when a current collector is constituted by stacking a plurality of metal plates, the metal plates are joined with resin etc. while the plate surfaces of the metal plates are generally pressed against each other in order to increase the contact between the metal plates. Therefore, upon manufacturing the current collector, air which exists between the metal plates outflows from between the joining layer and the metal plates, resulting in a possible poor joining which extends continuously from the perimeter of the current collector to the inside of the current collector. When such poor joining is caused, moisture may enter into the inside space of the current collector from the perimeter of the current collector, resulting in a corrosion of the metal plates. Therefore, a technique to reduce the corrosion of the metal plates has been longed for, for the current collector which is formed by stacking different kinds of metal plates.